Cable television (CATV) filters typically block channels from the full spectrum of channels offered to provide a limited or basic service to a subscriber at a lower price. Other CATV filters permit certain channels to pass through the filter while blocking the remainder. Because different models of filters block different groups of premium channels, the model numbers of the CATV filters are permanently printed, typically by roll stamping, into the metal housing of the filter. The filter tube is inserted into a support arbor after which raised hardened metal characters are rolled over the filter tube to leave an impression in the metal filter tube. Printed labels and ink labels are inadequate because of the filters' exposure to the environment and become impossible to read after sufficient exposure to the elements.
In addition, users are now requesting even more information to be permanently printed onto the filters, e.g., bar codes and/or serial numbers to control better the use of the filters. It is not practical to stamp such information on the filters using roll stamping.
Furthermore, stamping can deform the housing and change the internal characteristics of the performance of the filter, which fact can cause elaborate work-arounds when fabricating CATV filters.